Large Magellanic Cloud (LMC), combined hydrogen alpha (pink) and optical image. The LMC is a satellite galaxy of our Milky Way. Hydrogen alpha is a wavelength of light associated with ionised hydrogen, and is produced by emission nebulae. These are starbirth regions, huge clouds of gas whose hydrogen is ionised by radiation from hot young stars born within them. The largest of these regions is the Tarantula nebula (NGC 2070), at centre left. The LMC lies some 160,000 light years from Earth in the constellations Dorado and Mensa. The bar of stars (blue, lower left to centre right) suggests that the LMC was once a barred spiral galaxy, before being distorted by the far more massive Milky Way.